The present invention relates to a pulse generator, a pulse generating method, a communicating apparatus, and a communicating method applied to the ultra wideband (UWB) wireless communicating system.
Recently, as one wireless communicating system, the UWB wireless communicating system is becoming attractive. The UWB system not only uses an ultra wideband, but very short pulses on the order of nanoseconds or less (around several hundred picoseconds). The positions or amplitudes of pulses are modulated with transmission data. The UWB system allows a high transmission rate to be accomplished with a low power consumption.
In the UWB system, the transmission side modulates the positions or amplitudes of pulses of a pulse sequence that is output from a pulse generator with data to be transmitted so as to form a transmission signal. On the other hand, the reception side multiplies a reception signal by the same pulse sequence that was used on the transmission side so as to obtain reception data. When different pulse sequences are used by individual users to module and demodulate data, multiple access communications can be performed. The present invention uses a chaotic sequence for a UWB pulse generator. For example, Japanese Patent Laid-Open Publication No. 2003-140885 discloses a technology for digitally generating a chaotic sequence.
Another related art reference discloses a technology for accomplishing a spread spectrum communicating system for example CDMA communication system using a chaotic sequence. See, Japanese Patent No. 3234202.
However, the above-referenced cited art does not disclose the use of a chaotic sequence for the UWB system. In addition, the cited art does not describe a multiple access communication using a chaotic sequence for the UWB system.